The spherical roller bearing has double row rollers, the outer ring has 1 common spherical raceways, the inner ring has 2 raceways, and is inclined to an angle relative to the bearing axis. This ingenious structure makes it self aligning, so it is not easy to be affected by the angle of the shaft and the bearing box on the error or the axis bending. It is suitable for the occasion of the angle error caused by the installation error or the deflection of the shaft. The bearing not only can bear radial load, but also can bear axial load of bidirectional action.The inner hole of the roller bearing has two kinds of cylindrical and conical cones, and the conical conical taper is two kinds at 1:30 and 1:12. This conical inner hole bearing is fitted with a tight setting or retreating sleeve. The cone bore ball bearing can be conveniently and quickly assembled on the optical axis or the staircase shaft.